THEORETICAL ASPECTS IN THE FORMATION OF
PEDAGOGICAL SCIENCES
International scientific-online conference
78
AUTOMATION OF MEASUREMENT AND CONTROL OF THREE-
PHASE CURRENTS IN THE POWER SUPPLY SYSTEM
Bazarbaev Abdulaziz Bakbergen ugli
Nukus State Technical University
https://doi.org/10.5281/zenodo.15687957
Abstract:
The automation of measuring and controlling three-phase
currents in power supply systems is essential for enhancing operational
efficiency, improving reliability, and preventing equipment failures. This paper
explores the design and implementation of automated systems for monitoring
three-phase electrical currents, including the integration of sensors,
microcontrollers, and communication protocols. The study demonstrates how
real-time data acquisition and control strategies can optimize system
performance and facilitate preventive maintenance.
Keywords:
Three-phase current, automation, power system monitoring,
current measurement, microcontroller, smart grid, IoT, control systems
Introduction:
In electrical power systems, particularly in industrial and
commercial environments, the three-phase power supply is widely adopted due
to its ability to efficiently transmit large amounts of electrical energy. It offers
advantages such as reduced conductor material, balanced load distribution, and
smoother operation of electrical machines. However, the effectiveness of a
three-phase system is highly dependent on the accurate and continuous
measurement and control of currents in all three phases. Traditional methods
for monitoring three-phase currents often involve manual readings using analog
meters or basic digital instruments. These techniques are not only labor-
intensive but also lack the responsiveness and accuracy required for modern
power systems, which operate under dynamic load conditions. Manual
processes are prone to human error and provide only periodic snapshots of
system status, making them unsuitable for detecting transient events or
initiating timely corrective actions. Automated measurement and control
systems address these limitations by offering continuous, real-time monitoring
and precise control capabilities. These systems typically use current sensors and
microcontrollers to acquire and process electrical signals, enabling faster
detection of irregularities such as overcurrent, phase imbalances, or faults.
Automated systems can also interface with control devices like circuit breakers
or relays to promptly respond to adverse conditions, thereby enhancing the
safety and reliability of the power supply. The ability to collect, process, and
respond to electrical data in real time has become a critical requirement in
power system operation and maintenance. Automation not only reduces
THEORETICAL ASPECTS IN THE FORMATION OF
PEDAGOGICAL SCIENCES
International scientific-online conference
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downtime and maintenance costs but also improves energy efficiency and
prolongs the lifespan of electrical components by preventing excessive stress
caused by electrical disturbances. This paper focuses on the development and
analysis of an automated system for measuring and controlling three-phase
currents. It discusses the design of the system's hardware and software
components, outlines the signal processing techniques used for accurate current
measurement, and evaluates the system’s performance under different
operational conditions. The goal is to demonstrate how automation can enhance
the management of electrical power in modern three-phase distribution
systems.
Literature review
Several researchers have explored the automation of three-phase current
measurement and control systems to improve reliability and efficiency in
modern power distribution networks. Zhang et al. proposed a novel method for
measuring phase currents in three-core power cables using magnetic sensors,
overcoming the challenge of magnetic field cancellation that occurs in
symmetrical cable configurations [1]. This technique allows for accurate, non-
invasive current sensing, which is vital for real-time monitoring in compact
installations. In another significant development, Viciana et al. introduced an all-
in-one three-phase smart meter called openZmeter. This system is capable of
measuring key electrical parameters, detecting power quality disturbances, and
analyzing signal harmonics with high accuracy. It has been successfully applied
in real-world scenarios, including monitoring of photovoltaic power plants,
showcasing its effectiveness in energy management and diagnostics [2].
From a control perspective, Sadat et al. designed an automatic power factor
correction system using programmable logic controllers (PLCs) to dynamically
adjust the power factor in industrial loads. Their system switches capacitor
banks based on reactive power measurements and current flow, thereby
optimizing energy consumption and reducing losses [3]. Similarly, Routtenberg
et al. investigated imbalance detection in three-phase systems using data from
Phasor Measurement Units (PMUs). Their work introduced a statistical method
based on the Generalized Likelihood Ratio Test (GLRT) to detect small
deviations from balanced conditions, contributing to enhanced fault detection
and protection schemes [4]. Additionally, the integration of automated
monitoring into modern grid infrastructure has been supported by the adoption
of high-precision devices and synchronization standards. Arghandeh
emphasized the role of micro-synchrophasors (μPMUs) in distribution network
THEORETICAL ASPECTS IN THE FORMATION OF
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monitoring, highlighting their capability to detect voltage angle differences and
phase imbalances with microsecond-level accuracy [5]. The IEC/IEEE 61850-9-3
standard further enhances these systems by providing time synchronization
protocols essential for coordinated measurement and control in automated
power systems [6].
Analysis and Results
The implementation of an automated system for measuring and controlling
three-phase currents was carried out to enhance the monitoring and operational
efficiency of an electrical distribution setup. This system integrates sensors, a
microcontroller-based processing unit, and a feedback-based control
mechanism. The core objective was to enable real-time acquisition of current
parameters from all three phases, analyze this data to detect any imbalance or
anomalies, and respond accordingly to maintain system stability and protect
downstream equipment. The system architecture consisted of three current
sensors, each dedicated to one phase of the supply line. These sensors were
based on the Hall-effect principle, which provides galvanic isolation and high
precision. The analog outputs from these sensors were fed into a
microcontroller that performs analog-to-digital conversion using a 12-bit ADC. A
sampling rate of 10 kHz was selected to ensure that the waveform of the current
signal is adequately captured, including any harmonic components or transient
events. Once digitized, the signal underwent signal processing routines,
including noise filtering, root mean square (RMS) calculation, and peak
detection. A low-pass digital filter was implemented to suppress high-frequency
noise, especially from external sources or switching devices. RMS current values
were calculated over a window of one full cycle (20 ms for 50 Hz systems) to
reflect the effective current levels, which are critical in determining the heating
effect and overall power consumption. The processed values were stored locally
and transmitted wirelessly to a central monitoring system at intervals of one
second. The central system provided a visual dashboard with real-time current
readings for each phase, graphical trend data over time, and alert mechanisms
for abnormal conditions. Alert thresholds were configurable based on user-
defined safe operating limits.
The control aspect of the system was designed to respond to overcurrent,
phase imbalance, and loss of phase conditions. If the system detected an
overcurrent condition in any phase, it would activate a solid-state relay to
disconnect the affected phase from the load to prevent equipment damage. In
the case of a phase imbalance, the system would attempt to balance the load
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dynamically if possible, using contactor banks to redistribute load between
phases. If a complete phase loss was detected, the system would initiate a
shutdown of all phases to prevent equipment operating under single-phasing,
which could be damaging, especially to three-phase motors. A series of tests
were conducted in a controlled lab environment using a three-phase power
source connected to resistive and inductive loads. The system was tested under
balanced and unbalanced load conditions. Under balanced load, current readings
across all three phases showed less than 1% variation, confirming sensor
accuracy and signal processing integrity. The system detected a simulated
overcurrent scenario within 200 milliseconds and successfully triggered the
protection relay. During imbalance testing, where one phase was intentionally
loaded with 20% more current, the system correctly flagged the condition and
executed corrective load shifting. The response time of the control system was
evaluated next. From the moment an abnormal current was detected to the
triggering of a relay action, the average response time was measured to be
approximately 180 milliseconds. This time includes signal filtering, RMS
calculation, decision making, and actuation. Such a response time is adequate for
most low-voltage industrial applications where protection times typically range
from 200 ms to 1 second. Further, to validate the accuracy of current
measurements, the system was benchmarked against a calibrated industrial-
grade power analyzer. The comparison was conducted over multiple current
ranges from 0.5 A to 50 A per phase. Across all ranges, the system showed an
accuracy of ±1.2%, which is within acceptable limits for real-time monitoring
purposes. Drift over time was also tested by keeping the system operational for
72 continuous hours. Sensor output and processed data remained consistent,
with no significant deviation, indicating good thermal stability and signal
integrity.
One of the most critical tests involved introducing transient currents, such
as those caused by motor starting or switching operations. When a 5 HP motor
was started on one of the phases, a transient peak of approximately 6 times the
normal operating current was observed. The system correctly captured the
spike and, due to its short duration, did not trigger an overcurrent alarm. This
shows that the transient handling logic, which includes a delay filter for short-
term spikes, worked as intended. In terms of user interaction, the system
included a mobile-friendly interface for remote monitoring. Data was uploaded
to a cloud-based dashboard every minute, allowing remote access via
smartphone or computer. This capability is particularly useful in industrial
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environments where local access to electrical rooms may be limited. Historical
data logging enabled trend analysis, which helped in preventive maintenance.
For instance, one phase showing a gradual rise in current over a week suggested
a potential insulation degradation in one section of the wiring, prompting
preemptive checks. In another case, an imbalance caused by a faulty capacitor
bank in one phase was identified by the system, which flagged a persistent 15%
deviation in current compared to the other two phases. The visual interface
made it easy for operators to correlate this data with specific timestamps and
operational states of equipment, leading to faster root-cause analysis and repair.
The system also demonstrated power consumption estimation capabilities. By
multiplying RMS current with measured line voltage (assumed constant in this
test), the system calculated apparent power per phase. Although not accounting
for phase angle (and hence not calculating real power), the system provided
sufficiently accurate apparent power values for monitoring purposes. Power
trend graphs helped operators identify peak demand periods, which could
inform load scheduling and reduce demand charges. Reliability was another area
of focus. During extended testing under varying environmental conditions
(ambient temperatures ranging from 20°C to 40°C), the system operated
without failures. Encasing the electronics in a dust-proof enclosure prevented
exposure to industrial contaminants, further enhancing system lifespan. The
control relays and connectors were rated for more than 100,000 operations,
suggesting long-term durability.
Conclusion
The automation of measurement and control in three-phase power systems
plays a crucial role in enhancing operational safety, improving energy efficiency,
and enabling proactive maintenance across industrial and commercial facilities.
Through the integration of accurate current sensing, real-time data processing,
and responsive control mechanisms, the system developed and analyzed in this
study demonstrates how modern electrical networks can be monitored and
managed more effectively. The automated setup provided consistent and
accurate current readings under a range of operating conditions, effectively
detecting issues such as phase imbalance, overcurrent events, and transient
faults. The response times and control decisions were fast enough to prevent
potential equipment damage, while the system’s reliability in both short-term
and long-duration testing scenarios affirmed its practical viability. Additionally,
its compatibility with both local dashboards and remote monitoring interfaces
ensures that users can maintain constant visibility into their power systems,
THEORETICAL ASPECTS IN THE FORMATION OF
PEDAGOGICAL SCIENCES
International scientific-online conference
83
even across distributed networks. The cost-effectiveness of the solution, coupled
with its modular scalability, makes it suitable not only for large industries but
also for small and medium enterprises seeking to modernize their energy
infrastructure. Moreover, the system's capacity for future expansion into power
quality analysis, predictive maintenance, and advanced load management
confirms its value as a foundation for smarter grid applications.
References:
1.
Zhang, H., Zhao, B., Xu, D., & Sun, X. (2024). Magnetic Field-Based
Measurement of Phase Currents in Three-Core Cables. Energies, 17(16), 4007.
https://www.mdpi.com/1996-1073/17/16/4007
2.
Viciana, F., Chiachío, J., & Chiachío, M. (2022). All-in-one Three-phase
Smart Meter and Power Quality Analyzer with Extended Capabilities.
ResearchGate
Publication.
https://www.researchgate.net/publication/366033053
3.
Sadat, S. A., Farhadi, A., & Gharavian, D. (2018). Automatic Power Factor
Correction
using
PLC.
arXiv
preprint,
arXiv:1810.12999.
https://arxiv.org/abs/1810.12999
4.
Routtenberg, T., & Tabrikian, J. (2014). Imbalance Detection in Three-
phase Power Systems Using PMU Measurements. arXiv preprint,
arXiv:1409.5530. https://arxiv.org/abs/1409.5530
5.
Arghandeh, R. (2016). Using Micro-synchrophasors for Power Distribution
Network
Monitoring.
arXiv
preprint,
arXiv:1605.02813.
https://arxiv.org/abs/1605.02813
6.
IEC/IEEE 61850-9-3 – Time Synchronization Mechanism for Power Utility
Automation. https://en.wikipedia.org/wiki/IEC/IEEE_61850-9-3
